Method and apparatus for controlling airflow with a gapped trailing edge device having a flexible flow surface

ABSTRACT

A method and apparatus for controlling airflow with a gapped trailing edge device having a flexible flow surface. The airfoil can include a first portion having a first leading edge, a first flow surface, and a second flow surface facing opposite from the first flow surface. The airfoil can further include a second portion having a second leading edge and a trailing edge, with at least part of the second portion being positioned aft of the first portion. The second portion is moveable relative to the first portion between a first position and a second position, with the second leading edge separated from at least part of the first portion by an airflow gap when the second portion is in the second position. The second portion includes a flexible flow surface that has a first shape when the second portion is in the first position, and has a second shape different than the first shape when the second portion is in the second position.

TECHNICAL FIELD

[0001] The present application is directed toward methods andapparatuses for controlling the airflow around an airfoil having agapped trailing edge device with a flexible flow surface.

BACKGROUND

[0002] Modern high-speed, subsonic commercial aircraft typically havewings with a variety of leading edge and trailing edge devices to changethe shape of the airfoil as the flight conditions change. Such airfoilscan include flexible panels at the airfoil leading edge, as disclosed inU.S. Pat. Nos. 3,994,451; 4,171,787; 4,351,502; 4,475,702; and4,706,913. Other airfoils include flexible trailing edge panels, such asthose disclosed in U.S. Pat. Nos. 4,131,253 and 4,312,486.

[0003] Other existing devices include variable camber, leading edgeKrueger-type flaps, such as those disclosed in U.S. Pat. Nos. 3,504,870;3,556,439; 3,743,219; 3,910,530; 3,941,334; 4,189,120; 4,189,122;4,262,868; 4,427,168; 5,158,252; and 5,474,265.

[0004] One potential drawback with some of the foregoing devices is thatthe mechanisms required to actuate the devices can be complex.Accordingly, the cost of installing and maintaining the devices can berelatively high. Another potential drawback is that the devices may notcontrol the airflow over the wing in an optimal manner at all settings.Accordingly, the aerodynamic performance of the airfoils with theleading and/or trailing edge devices deployed may cause some dragincrease and corresponding decrease in aircraft performance.

SUMMARY

[0005] The present invention is directed toward methods and apparatusesfor controlling airflow with a gapped trailing edge device having aflexible flow surface. An airfoil in accordance with one aspect of theinvention includes a first portion having a first leading edge, a firstflow surface, and a second flow surface facing opposite from the firstflow surface. The airfoil can further include a second portion having asecond leading edge and a trailing edge with at least part of the secondportion being positioned aft of the first portion. The second portion ismoveable relative to the first portion between a first position and asecond position, wherein the second leading edge is separated from atleast part of the first portion by an airflow gap when the secondportion is in the second position. The second portion further includes aflexible flow surface having a first shape when the second portion is inthe first position and a second shape different than the first shapewhen the second portion is in the second position. A guide structure iscoupled between the first portion and the second portion.

[0006] In a further aspect of the invention, the guide structure caninclude a roller and slot arrangement. In yet a further aspect of theinvention, the guide structure can include a four-bar linkagearrangement. For example, the first portion can include a wing bodyhaving a hinge support, and the second portion can include a trailingedge body pivotably coupled to the hinge support, and a leading edgebody coupled to the trailing edge body with the flexible flow surface. Acoupling link can be pivotably coupled between the hinge support and theleading edge body. In another aspect of the invention, the leading edgebody can be pivotably coupled to the trailing edge body.

[0007] A method in accordance with one aspect of the invention includesvarying a geometry of an airfoil having a first portion and a secondportion moveably coupled to the first portion. The method can includemoving the second portion of the airfoil relative to the first portionof the airfoil from a first position to a second position, with at leastpart of the second portion being positioned aft of the first portion.The method can further include forming an airflow gap by separating atleast part of the second portion from the first portion, and changingthe shape of a flexible flow surface of the second portion from a firstshape to a second shape different than the first shape as the secondportion moves from the first position to the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a partially schematic, cross-sectional side view of anairfoil having a movable trailing edge portion in accordance with anembodiment of the invention.

[0009]FIG. 2 is an enlarged, partially schematic illustration of an aftpart of the airfoil shown in FIG. 1.

[0010] FIGS. 3A-3C illustrate an airfoil having a movable trailing edgedevice deployed in accordance with embodiments of the invention.

[0011] FIGS. 4A-4H schematically illustrate an aircraft having aplurality of movable trailing edge portions, along with settings for thetrailing edge portions at a variety of flight conditions.

[0012]FIG. 5 is a partially schematic, cross-sectional side view of anairfoil having a movable aft portion in accordance with anotherembodiment of the invention.

[0013] FIGS. 6A-6C illustrate the airfoil shown in FIG. 5 deployed to avariety of positions in accordance with embodiments of the invention.

[0014] FIGS. 7A-7B are partially schematic, cross-sectional side viewsof an airfoil having a movable aft portion in accordance with yetanother embodiment of the invention.

DETAILED DESCRIPTION

[0015] The present disclosure describes airfoils having trailing edgedevices with flexible flow surfaces, and methods for operating suchairfoils. Many specific details of certain embodiments of the inventionare set forth in the following description and FIGS. 1-6C to provide athorough understanding of these embodiments. One skilled in the art,however, will understand that the present invention may have additionalembodiments, and that the invention may be practiced without several ofthe details described below.

[0016]FIG. 1 is a partially schematic, cross-sectional side view of anairfoil 100 having a first, fixed portion 101 and a second, movableportion 102 that moves relative to the first portion 101 in accordancewith an embodiment of the invention. In one aspect of this embodiment,the first portion 101 can include a wing body 110 having a first leadingedge 111 and a first trailing edge 112 that defines an open, aft-facingcove 113. The second portion 102 can include a trailing edge body 120coupled to a leading edge body 130, both of which extend aft from thewing body 110. The trailing edge body 120 can have a second trailingedge 121 and the leading edge body 130 can have a second leading edge131 that fits into the cove 113 of the wing body 110. The second portion102 can move relative to the first portion 101 from a neutral position(shown in FIG. 1) to a variety of deployed positions, as described ingreater detail below with reference to FIGS. 2-3B.

[0017]FIG. 2 is an enlarged view of the aft portion of the airfoil 100described above with reference to FIG. 1. As shown in FIG. 2, the firstportion 101 can have an upper surface 114 and a lower surface 115 facingopposite from the upper surface 114. The second portion 102 of theairfoil 100 can include an upper surface 103 and a lower surface 104facing opposite from the upper surface 103. When the second portion 102is in the neutral position (as shown in FIG. 2), the second portion 102is at least partially sealed against the first portion 101, with theupper surfaces 114 and 103 forming a generally continuous upper contour,and the lower surfaces 115 and 104 forming a generally continuous lowercontour.

[0018] In one aspect of an embodiment shown in FIG. 2, the secondportion 102 can be coupled to the first portion 101 with a guidestructure 150. In a further aspect of this embodiment, the guidestructure 150 can include a series of pivots and links arranged to forma four-bar linkage. In other embodiments, the guide structure 150 canhave other arrangements, such as a six-bar linkage or a roller/trackarrangement. In any of these embodiments, the second portion 102 is atleast partially sealed against the first portion 101 when in the neutralposition, and can move relative to the first portion 110 to form agapped trailing edge configuration, as described in greater detailbelow.

[0019] In one embodiment, the wing body 110 can include a hinge support153 that extends aft from the cove 113. The trailing edge body 120 canbe pivotably coupled to the hinge support 153 with a lower pivot joint152. The trailing edge body 120 can also be pivotably coupled to theleading edge body 130 at an upper pivot joint 154. The leading edge body130 can be coupled to the hinge support 153 with a coupling link 151having first and second coupling hinges 155 (shown as coupling hinges155 a and 155 b). Accordingly, the coupling link 151 can complete thefour-bar linkage arrangement.

[0020] A flexible flow surface 140 extends from an aft attachment point142 on the trailing edge body 120 to a forward attachment point 143 onthe leading edge body 130. Accordingly, the flexible flow surface 140can change shape as the second portion 102 pivots relative to the firstportion 101. In one embodiment, the flexible flow surface 140 caninclude a metal sheet, such as an aluminum sheet or a titanium sheet. Inanother embodiment, the flexible flow surface 140 can include acomposite material, such as a carbon fiber material. In still furtherembodiments, the flexible flow surface 140 can include other pliablematerials that can withstand the aerodynamic loads of high-speed flight.The pivoting action for the four-bar linkage can be provided by anactuator 160 coupled between the wing body 110 and a point on thetrailing edge body 120 spaced apart from the lower pivot joint 152. Forexample, the actuator can include an electric, pneumatic and/orhydraulic device, coupled above the lower pivot joint 152 (as shown inFIG. 2) or below the lower pivot joint 152. In other embodiments, theairfoil 100 can include other actuation arrangements.

[0021] In one aspect of an embodiment shown in FIG. 2, the leading edgebody 130 can include a series of spanwise, spaced apart flanges 133covered by a skin 134 that defines a portion of the second leading edge131. In another embodiment, the leading edge body 130 can include agenerally solid element that extends span-wise and defines the secondleading edge 131. The trailing edge body 120 can also include a seriesof spanwise, spaced apart flanges 123 and a skin 124 that covers theflanges 123 to define the upper surface 103, the second trailing edge121, and an aft segment 122 of the lower surface 104. The leading edgebody 130 can include a forward segment 132 of the lower surface 104. Theforward segment 132 and the aft segment 122 can form a generallycontinuous contour when the second portion 102 is in the neutralposition, and can be spaced apart from each other when the secondportion 102 moves to its deployed positions, as described in greaterdetail below with reference to FIGS. 3A-3C.

[0022]FIG. 3A is a partially schematic, cross-sectional side view of theairfoil 100 with the second portion 102 deflected downwardly by 20°relative to the neutral position shown in FIGS. 1 and 2. As shown inFIG. 3A, deploying the second portion 102 opens a gap 141 between thesecond leading edge 131 of the leading edge body 130, and the firsttrailing edge 112 of the wing body 110. Deploying the second portion 102also opens a space 135 between the aft segment 122 and the forwardsegment 132 of the lower surface 104. The gap 141 is configured to allowa portion of the flow passing along the lower surface 115 of the wingbody 110 to flow through the gap 141 to the upper surface 103 of thesecond portion 102. The space 135 is configured to have a small and/ornegligible impact on the airflow passing along the lower surface 104 ofthe second portion 102.

[0023] The second portion 102 can be further deployed to additionaldownwardly deflected positions. For example, as shown in FIG. 3B, thesecond portion 102 can be deployed to a 40° downwardly deflectedposition. In other embodiments, the second portion 102 can have othermaximum downwardly deflected positions, and in any of these embodiments,the second portion 102 can be deflected to any intermediate positionbetween the neutral or undeflected position (shown in FIGS. 1 and 2) andthe maximum downwardly deflected position shown in FIG. 3B. In any ofthese embodiments, when the second portion 102 is deflected downwardly,it can increase the lift of the airfoil 100. Accordingly, multiplesecond portions 102 can be deployed symmetrically during take-off andlanding, or asymmetrically for roll control, as described in greaterdetail below with reference to FIGS. 4A-4H.

[0024] The second portion 102 can also be deployed upwardly from theneutral position, as shown in FIG. 3C. In one aspect of this embodiment,the second portion 102 can be deflected upwardly by up to 30° or more,relative to the first portion 101. Accordingly, the second portion 102can act as a lift spoiler, for example during landing approach and/orafter touchdown.

[0025] A further characteristic of the foregoing embodiments is that theflexible flow surface 140 changes shape as the second portion 102 movesrelative to the first portion 101. Accordingly, the flexible flowsurface 140 can provide a smooth, aerodynamic shape for the secondleading edge 131 of the second portion 102, even as the second portion102 undergoes substantial deflections from its neutral position. Thesmooth, aerodynamic shape can promote attached airflow over the secondportion 102 even at extreme downward deflections.

[0026]FIG. 4A is a partially schematic illustration of an aircraft 170having a plurality of airfoils with first and second portions arrangedin a manner generally similar to that described above with reference toFIGS. 1-3C. For example, the aircraft 170 can include a wing airfoil 100a and a horizontal stabilizer airfoil 100 b. The wing airfoil 100 a caninclude a first portion 101 a fixed to a fuselage 171 of the aircraft170, and a plurality of second portions 102 (five are shown in FIG. 4Aas second portions 102 a-102 e), all of which are movable relative tothe first portion 101 a. The horizontal stabilizer 100 b can include afirst portion 101 b and a second portion 102 f that is movable relativeto the first portion 101 b. The second portion 102 f can be selectivelydeployed upwardly and downwardly to control the pitch of the aircraft170. The second portions 102 a-102 e can be selectively deployed in avariety of manners corresponding to a variety of flight conditions, asdescribed in greater detail below with reference to FIGS. 4B-4H.

[0027] FIGS. 4B-4H are schematic illustrations of the second portions102 a-102 e deployed in a variety of combinations depending upon theflight condition of the aircraft 170. In each of FIGS. 4B-4H, line 125represents the neutral position for each second portion 102, line 126represents a steady state deflected position for each second portion102, and phantom lines 127 represent time-varying deflections of thesecond portions 102. For example, as shown in FIG. 4B (representing anormal take-off configuration), second portions 102 a-102 e can bedeflected downwardly 100 from the neutral position to a steady stateposition, and then outboard second portions 102 d and 102 e can bedeflected upwardly and downwardly from the 100 position in atime-varying manner to provide for a low speed roll control. For a shorttake-off (shown in FIG. 4C), the second portions 102 a-102 e can bedeflected downwardly by 20°, with each second portion 102 a-102 edeflected upwardly or downwardly in a time-varying manner as needed forlow speed roll control. In a typical cruise condition (FIG. 4D) all thesecond portions 102 a-102 e are moved to the neutral position, withsmall upward and downward deflections as needed for local trim and/orgust load alleviation. As shown in FIG. 4E, second portions 102 b and102 c can be deployed during high speed flight to provide for high speedroll control. Second portions 102 b and 102 c on opposite sides of thefuselage 171 (FIG. 4A) will be deployed in opposite directions toachieve the required roll moment.

[0028] As shown in FIG. 4F, second portions 102 b-102 d can be deployedin flight to increase the drag of the airfoil 100 a, providing anin-flight braking mechanism. As shown in FIG. 4G, all the secondportions 102 a-102 e can be deflected downwardly by 40° during landing.After the aircraft is landed, some or all of the second portions 102 athrough 102 e can be deflected upwardly as shown in FIG. 4H, to spoilthe lift of the airfoil 100 a.

[0029] In other embodiments, the aircraft 170 shown in FIG. 4A can haveother combinations of second portions 102, and/or the second portions102 can be deployed in other manners, depending on flight condition. Theairfoils 100 a and/or 100 b can be installed on aircraft 170 having atypical swept wing, twin engine configuration (as shown in FIG. 4A) orthese elements can be installed on any aircraft that benefits fromdeployable lift control devices.

[0030] One feature of embodiments of the airfoils described above withreference to FIGS. 1-4H is that the flexible flow surface 140 can changeshape as the second portion 102 deflects relative to the first portion101. An advantage of this arrangement is that the flow surface definedby the second leading edge 131 and the upper surface 103 can be smoothand continuous, even as the second portion 102 deploys to substantialdeflection angles relative to the neutral position, and even as the gap141 between the second portion 102 and the first portion 101 increasesin size. Accordingly, this arrangement can maintain a smooth flow of airover the second portion 102 even at high lift settings.

[0031] Another feature of embodiments of the airfoils described abovewith reference to FIGS. 1-4H is that the guide structure 150 thatcontrols the motion of the second portion 102 can include a relativelysimple four-bar linkage arrangement. An advantage of this arrangement isthat the four-bar linkage has relatively few moving parts and isaccordingly simpler to install and maintain than some conventionalarrangements. A further advantage of this arrangement is that the guidestructure 150 can be entirely contained or almost entirely containedwithin the contour defined by the upper and lower surfaces of the firstportion 101 and the second portion 102. Accordingly, the need for large,movable fairings (which can significantly increase aircraft drag) can bereduced and/or eliminated.

[0032] In other embodiments, the airfoils can have other arrangementsthat also include smooth surfaced, gapped deployable trailing edgedevices. For example, as shown in FIG. 5, an airfoil 500 can include afirst portion 501 coupled to a second portion 502 with a guide structure550 in accordance with another embodiment of the invention. In oneaspect of this embodiment, the first portion 501 can include a wing body510 having an upper surface 514, a lower surface 515, a first trailingedge 512, and a hinge support 553 that extends aft from the firsttrailing edge 512. The second portion 502 can include a trailing edgebody 520 (a portion of which is visible in FIG. 5) coupled at a lowerpivot joint 552 to the hinge support 553. The second portion 502 canfurther include a leading edge body 530 coupled to the hinge support 553with a coupling link 551. An actuator 560 can be coupled to the secondportion 102 at a pivot point 554 to move the second portion 102 relativeto the first portion 101.

[0033] Unlike the configuration described above with reference to FIGS.1-4H, the leading edge body 530 is not pivotably coupled directly to thetrailing edge body 520, but is instead linked to the trailing edge body520 only via a flexible flow surface 540. Accordingly, the flexible flowsurface 540 is connected to the trailing edge body 520 at an aftattachment point 542, and is attached to the leading edge body 530 at aforward attachment point 543. The trailing edge body 520 has an uppersurface 503 and a lower surface 504 that defines an aft segment 522. Theleading edge body 530 has a second leading edge 531 that defines aforward segment 532. The forward segment 532 forms a continuous contourwith the aft segment 522 when the second portion 502 is in the neutralposition, and breaks with the aft segment 522 when the second portion502 is deflected, as described in greater detail below with reference toFIGS. 6A-6C.

[0034] FIGS. 6A-6C illustrate the airfoil 500 with the second portion502 deflected to a variety of deployed positions in accordance withembodiments of the invention. For example, as shown in FIG. 6A, thesecond portion 502 can be deflected downwardly 20° from the neutralposition to form a gap 541 between the first trailing edge 512 of thewing body 510, and the second leading edge 531 of the leading edge body530. As the second portion 502 deflects downwardly, the flexible flowsurface 540 changes shape to maintain a smooth, continuous flow surfacebetween the leading edge body 530 and the trailing edge body 520. At thesame time, a space 535 opens between the aft segment 522 and the forwardsegment 532.

[0035] As shown in FIG. 6B, the second portion 502 can be deflected to amaximum downward deployment of 450 relative to the neutral position inone embodiment. In other embodiments, the second portion 502 can haveother maximum downward deflections. In one aspect of this embodiment,the pivot connection between the second portion 502 and the actuator 560can project above the flexible flow surface 540 as the second portion502 deflects downwardly. Alternatively, the pivot connection can bepositioned to remain below the flexible flow surface 540 as the secondportion 502 moves. As shown in FIG. 6C, the second portion 502 can bedeflected upwardly to a maximum deflection of 20° from the neutralposition. In other embodiments, the second portion 502 can have othermaximum upward deflections.

[0036] In still further embodiments, the airfoils can have otherarrangements that also include smooth surfaced, gapped deployabletrailing edge devices. For example, as shown in FIG. 7A, an airfoil 700can include a first portion 701 coupled to a second portion 702 with aguide structure 750 in accordance with yet another embodiment of theinvention. In one aspect of this embodiment, the first portion 701 caninclude a wing body 710 having an upper surface 714, a lower surface715, a first trailing edge 712, and a hinge support 753 that extends aftfrom the first trailing edge 712. The second portion 702 can include atrailing edge body 720 (a portion of which is visible in FIG. 7A)coupled at a lower pivot joint 752 to the hinge support 753. The secondportion 702 can further include a leading edge body 730 coupled to thetrailing edge body 720 at an upper pivot joint 754, and coupled to thehinge support 753 with a roller 751. The roller 751 can be received in aguide slot 755 of the hinge support 753. An actuator 760 can be coupledto the second portion 702 to move the second portion 702 relative to thefirst portion 701. The motion of the second portion 702 relative to thefirst portion 701 is controlled in part by the path the roller 751 takesas it travels in the guide slot 755.

[0037] The airfoil 700 further includes a flexible flow surface 740connected to the trailing edge body 720 at an aft attachment point 742,and attached to the leading edge body 530 at a forward attachment point743. The trailing edge body 720 has an upper surface 703 and a lowersurface 704 that defines an aft segment 722. The leading edge body 730has a second leading edge 731 that defines a forward segment 732. Theforward segment 732 forms a continuous contour with the aft segment 722when the second portion 702 is in the neutral position (as shown in FIG.7A), and breaks with the aft segment 722 when the second portion 702 isdeflected, as described in greater detail below with reference to FIG.7B.

[0038]FIG. 7B illustrates the airfoil 700 with the second portion 702deflected downwardly 45° from the neutral position to form a gap 741between the first trailing edge 712 of the wing body 710, and the secondleading edge 731 of the leading edge body 730. As the second portion 702deflects downwardly, the flexible flow surface 740 changes shape tomaintain a smooth, continuous flow surface between the leading edge body730 and the trailing edge body 720. At the same time, a space 735 opensbetween the aft segment 722 and the forward segment 732. The secondportion 702 can be deflected downwardly by other angles greater or lessthan 450, and can also be deflected upwardly relative to the neutralposition, as described above.

[0039] From the foregoing, it will be appreciated that specificembodiments of the invention have been described herein for purposes ofillustration, but that various modifications may be made withoutdeviating from the spirit and scope of the invention. For example, thesecond or movable portions 102 described above can be implemented onairfoils other than wings and aft-mounted horizontal stabilizers, forexample, on canards or any other lift-generating surface. The guidestructure that couples the second portions 102 to the first portions 101can include arrangements other than the four-bar linkage arrangementsshown in the figures. For example, the guide structures can includesix-bar or other multiple linkage arrangements. Accordingly, theinvention is not limited except as by the appended claims.

We claim:
 1. An airfoil assembly, comprising: a first portion having afirst leading edge, a first flow surface and a second flow surfacefacing opposite from the first flow surface; a second portion having asecond leading edge and a trailing edge, at least part of the secondportion being positioned aft of the first portion, the second portionbeing movable relative to the first portion between a first position anda second position, wherein the second leading edge is separated from atleast part of the first portion by an airflow gap when the secondportion is in the second position, and wherein the second portionincludes a flexible flow surface, the flexible flow surface having afirst shape when the second portion is in the first position, theflexible flow surface having a second shape different than the firstshape when the second portion is in the second position; and a guidestructure coupled between the first portion and the second portion. 2.The airfoil of claim 1 wherein the guide structure includes a four-barlinkage arrangement.
 3. The airfoil of claim 1 wherein the guidestructure includes a roller and slot arrangement.
 4. The airfoil ofclaim 1 wherein the first portion includes a hinge support, and whereinthe second portion includes a trailing edge body and a leading edgebody, the leading edge body being connected to the flexible flowsurface, further wherein the guide structure includes a first pivotjoint between the trailing edge body and the hinge support, a secondpivot joint between the trailing edge body and the leading edge body,and a coupling link pivotably coupled between the hinge support and theleading edge body.
 5. The airfoil of claim 1 wherein the guide structureincludes a pivot joint between the first portion and the second portion.6. The airfoil of claim 1 wherein the second portion includes a thirdsurface facing opposite from the flexible flow surface, and wherein thefirst, second, third and flexible flow surfaces define a flow contour,further wherein the guide structure includes a pivot joint between thefirst portion and the second portion, the pivot joint being positionedat or within the flow contour.
 7. The airfoil of claim 1 wherein theguide structure includes a first pivot joint between the first portionand the second portion, and wherein the guide structure further includesa coupling link pivotably coupled between the first portion and thesecond portion at second and third pivot joints.
 8. The airfoil of claim1 wherein the second portion includes a leading edge body attached tothe flexible flow surface, and wherein the guide structure includes apivot joint between the first portion and the second portion, andwherein the guide structure further includes a coupling link pivotablycoupled between the first portion and the leading edge body.
 9. Theairfoil of claim 1 wherein the second portion deflects downwardlyrelative to the first portion when the second portion is in the secondposition.
 10. The airfoil of claim 1 wherein the second portion deflectsdownwardly relative to the first portion when the second portion is inthe second position, and wherein the second portion is movable to athird position with the second portion deflected upwardly relative tothe first portion.
 11. The airfoil of claim 1 wherein the second portionat least partially seals the gap when the second portion is in the firstposition.
 12. The airfoil of claim 1 wherein the flexible flow surfaceforms a generally continuous first contour with the first surface of thefirst portion when the second portion is in the first position, andwherein the second portion further includes a third surface facingopposite from the flexible flow surface, the third surface forming agenerally continuous second contour with the second surface of the firstportion when the second portion is in the second position, furtherwherein the third surface has a forward section and an aft section, theforward and aft sections forming a generally continuous third contourwhen the second portion is in the first position, the forward and aftsections being spaced apart from each other when the second portion isin the second position.
 13. The airfoil of claim 1, further comprisingan actuator coupled between the first portion and the second portion,the actuator being positioned to selectively move the second portionbetween the first and second positions.
 14. The airfoil of claim 1wherein the second portion is configured to operate as at least one of aflap, an aileron, an elevator, a speed brake, and a spoiler.
 15. Theairfoil of claim 1 wherein the first portion includes a primary liftingsurface for an aircraft.
 16. An airfoil, comprising: a first portionthat includes a wing body having a first leading edge, a first flowsurface, a second flow surface facing opposite from the first flowsurface, and a hinge support; and a second portion movably coupled tothe first portion, the second portion including: a trailing edge bodyhaving a trailing edge positioned aft of the wing body, the trailingedge body being pivotably coupled to the hinge support at a pivot jointto move relative to the wing body between a first position and a secondposition; a leading edge body coupled to the trailing edge body andhaving a second leading edge, wherein the second leading edge isseparated from at least part of the wing body by an airflow gap when thetrailing edge body is in the second position; a flexible flow surfaceconnected between the trailing edge body and the leading edge body, theflexible flow surface having a first shape when the trailing edge bodyis in the first position, the flexible flow surface having a secondshape different than the first shape when the trailing edge body is inthe second position; and a coupling link pivotably coupled between thehinge support and the leading edge body.
 17. The airfoil of claim 16wherein the trailing edge body includes a third surface facing oppositefrom the flexible flow surface, and wherein the first, second, third andflexible flow surfaces define a flow contour, further wherein the pivotjoint between the hinge support and the trailing edge body is positionedat or within the flow contour.
 18. The airfoil of claim 16 wherein thetrailing edge body deflects downwardly relative to the wing body whenthe trailing edge body is in the second position.
 19. The airfoil ofclaim 16 wherein the trailing edge body deflects downwardly relative tothe wing body when the trailing edge body is in the second position, andwherein the trailing edge body is movable to a third position with thetrailing edge body deflected upwardly relative to the wing body.
 20. Theairfoil of claim 16 wherein the leading edge body at least partiallyseals the gap when the trailing edge body is in the first position. 21.The airfoil of claim 16 wherein the flexible flow surface forms agenerally continuous first contour with the first surface of the wingbody when the trailing edge body is in the first position, and whereinthe trailing edge body includes a third surface facing opposite from theflexible flow surface, the third surface forming a generally continuoussecond contour with the second leading edge when the trailing edge bodyis in the second position, the third surface being separated from thesecond leading edge when the trailing edge body is in the secondposition.
 22. The airfoil of claim 16, further comprising an actuatorcoupled between the wing body and the trailing edge body, the actuatorbeing positioned to selectively move the trailing edge body between thefirst and second positions.
 23. The airfoil of claim 16 wherein theflexible flow surface includes a composite material.
 24. An airfoil,comprising: a first portion that includes a wing body having a firstleading edge, a first flow surface, a second flow surface facingopposite from the first flow surface, and a hinge support; and a secondportion movably coupled to the first portion, the second portionincluding: a trailing edge body having a trailing edge positioned aft ofthe wing body, the trailing edge body being pivotably coupled at a pivotjoint to the hinge support to move relative to the wing body between afirst position and a second position; a leading edge body having asecond leading edge and being pivotably coupled to the trailing edgebody, wherein the second leading edge is separated from at least part ofthe wing body by an airflow gap when the trailing edge body is in thesecond position; a flexible flow surface connected between the trailingedge body and the leading edge body, the flexible flow surface having afirst shape when the trailing edge body is in the first position, theflexible flow surface having a second shape different than the firstshape when the trailing edge body is in the second position; and acoupling link pivotably coupled between the hinge support and theleading edge body.
 25. The airfoil of claim 24 wherein the trailing edgebody includes a third surface facing opposite from the flexible flowsurface, and wherein the first, second, third and flexible flow surfacesdefine a flow contour, further wherein the pivot joint between the hingesupport and the trailing edge body is positioned at or within the flowcontour.
 26. The airfoil of claim 24 wherein the trailing edge bodydeflects downwardly relative to the wing body when the trailing edgebody is in the second position.
 27. The airfoil of claim 24 wherein thetrailing edge body deflects downwardly relative to the wing body whenthe trailing edge body is in the second position, and wherein thetrailing edge body is movable to a third position with the trailing edgebody deflected upwardly relative to the wing body.
 28. The airfoil ofclaim 24 wherein the leading edge body at least partially seals the gapwhen the trailing edge body is in the first position.
 29. The airfoil ofclaim 24 wherein the flexible flow surface forms a generally continuousfirst contour with the first surface of the wing body when the trailingedge body is in the first position, and wherein the trailing edge bodyincludes a third surface facing opposite from the flexible flow surface,the third surface forming a generally continuous second contour with thesecond leading edge when the trailing edge body is in the secondposition, the third surface being separated from the second leading edgewhen the trailing edge body is in the second position.
 30. The airfoilof claim 24, further comprising an actuator coupled between the wingbody and the trailing edge body, the actuator being positioned toselectively move the trailing edge body between the first and secondpositions.
 31. An airfoil, comprising: a first portion, the firstportion including: a wing body having a first leading edge, a first flowsurface and a second flow surface facing opposite from the first flowsurface; and a hinge support depending from the wing body; a secondportion, the second portion including: a trailing edge body having atrailing edge positioned aft of the wing body, the trailing edge bodybeing pivotably coupled to the hinge support at a pivot joint to moverelative to the wing body between a first position and a secondposition; a leading edge body having a second leading edge separatedfrom the wing body by an airflow gap when the trailing edge body is inthe second position; and a flexible flow surface connected between thetrailing edge body and the leading edge body, the flexible flow surfacehaving a first shape when the trailing edge body is in the firstposition, the flexible flow surface having a second shape different thanthe first shape when the trailing edge body is in the second position; acoupling link pivotably coupled between the hinge support and theleading edge body as the trailing edge body moves between the firstposition and the second position; and an actuator coupled between thewing body and the trailing edge body, the actuator being positioned toselectively move the trailing edge body between the first and secondpositions.
 32. The airfoil of claim 31 wherein the leading edge body ispivotably coupled to the trailing edge body.
 33. The airfoil of claim 31wherein the trailing edge body includes a third surface facing oppositefrom the flexible flow surface, and wherein the first, second, third andflexible flow surfaces define a flow contour, further wherein the pivotjoint between the hinge support and the trailing edge body is positionedat or within the flow contour.
 34. The airfoil of claim 31 wherein thetrailing edge body deflects downwardly relative to the wing body whenthe trailing edge body is in the second position.
 35. The airfoil ofclaim 31 wherein the trailing edge body deflects downwardly relative tothe wing body when the trailing edge body is in the second position, andwherein the trailing edge body is movable to a third position with thetrailing edge body deflected upwardly relative to the wing body.
 36. Theairfoil of claim 31 wherein the leading edge body at least partiallyseals the gap when the trailing edge body is in the first position. 37.The airfoil of claim 31 wherein the flexible flow surface forms an atleast generally continuous first contour with the first surface of thewing body when the trailing edge body is in the first position, andwherein the trailing edge body includes a third surface facing oppositefrom the flexible flow surface, the third surface forming an at leastgenerally continuous second contour with the second leading edge whenthe trailing edge body is in the second position, the third surfacebeing separated from the second leading edge when the trailing edge bodyis in the second position.
 38. An airfoil, comprising: a first portionhaving a first leading edge, a first flow surface and a second flowsurface facing opposite from the first flow surface; and a plurality ofsecond portions positioned aft the first leading edge, each secondportion having a second leading edge and a trailing edge and beingmovable relative to the first portion between a first position and asecond position, wherein the second leading edge of each second portionis separated from the first portion of the airfoil by a gap when thesecond portion is in the second position, and wherein each secondportion includes a flexible flow surface, each flexible flow surfacehaving a first shape when a corresponding one of the second portions isin the first position, each flexible flow surface having a second shapedifferent than the first shape when the corresponding second portion isin the second position; and a plurality of guide structures, with eachguide structure coupled between the first portion and a correspondingone of the second portions.
 39. The airfoil of claim 38 wherein each ofthe second portions is movable relative to the first portionindependently of the other second portions.
 40. The airfoil of claim 38wherein at least one of the plurality of guide structures includes afour-bar linkage arrangement.
 41. The airfoil of claim 38 wherein atleast one of the plurality of guide structures includes a roller andslot arrangement.
 42. The airfoil of claim 38 wherein at least one ofthe plurality of guide structures includes a pivot joint between thefirst portion and a corresponding one of the second portions.
 43. Theairfoil of claim 38 wherein at least one of the plurality of guidestructures includes a first pivot joint between the first portion and acorresponding one of the second portions, and wherein the at least oneguide structure further includes a coupling link pivotably coupledbetween the first portion and the corresponding second portion at secondand third pivot joints.
 44. The airfoil of claim 38 wherein at least oneof the second portions includes a leading edge body attached to one ofthe flexible flow surfaces, and wherein at least one of the guidestructures includes a pivot joint between the first portion and the atleast one second portion, and wherein the at least one guide structurefurther includes a coupling link pivotably coupled between the firstportion and the leading edge body.
 45. The airfoil of claim 38 whereinthe first portion includes at least one hinge support, and wherein atleast one of the second portions includes a trailing edge body and aleading edge body, the leading edge body being connected to one of theflexible flow surfaces, wherein at least one of the guide structuresincludes a first pivot joint between the trailing edge body and the atleast one hinge support, a second pivot joint between the trailing edgebody and the leading edge body, and a coupling link pivotably coupledbetween the at least one hinge support and the leading edge body. 46.The airfoil of claim 38 wherein at least one of the second portionsdeflects downwardly relative to the first portion when the at least onesecond portion is in the second position.
 47. The airfoil of claim 38wherein at least one of the second portions deflects downwardly relativeto the first portion when the second portion is in the second position,and wherein the at least one second portion is movable to a thirdposition with the at least one second portion deflected upwardlyrelative to the first portion.
 48. The airfoil of claim 38 wherein atleast one of the second portions at least partially seals the gap whenthe at least one second portion is in the first position.
 49. Theairfoil of claim 38, further comprising an actuator coupled between thefirst portion and at least one of the second portions, the actuatorbeing positioned to selectively move the at least one second portionbetween the first and second positions.
 50. A method for varying ageometry of an airfoil having a-first portion and a second portionmovably coupled to the first portion, the method comprising: moving thesecond portion of the airfoil relative to the first portion of theairfoil from a first position to a second position, with at least partof the second portion being positioned aft of the first portion; formingan airflow gap by separating at least part of the second portion fromthe first portion; and changing a shape of a flexible flow surface ofthe second portion from a first shape to a second shape different thanthe first shape as the second portion moves from the first position tothe second position.
 51. The method of claim 50 wherein moving thesecond portion of the airfoil includes actuating a four-bar linkagearrangement.
 52. The method of claim 50 wherein moving the secondportion of the airfoil includes moving a roller within a guide slot. 53.The method of claim 50 wherein moving the second portion of the airfoilincludes pivoting the second portion relative to the first portion. 54.The method of claim 50 wherein moving the second portion of the airfoilincludes pivoting the second portion about a first pivot joint betweenthe first portion and the second portion and rotating a coupling linkpivotably coupled between the first portion and the second portion atsecond and third pivot joints.
 55. The method of claim 50 wherein thesecond portion includes a leading edge body attached to the flexibleflow surface, and wherein the airfoil includes a pivot joint between thefirst portion and the second portion and a coupling link pivotablycoupled between the first portion and the leading edge body, furtherwherein moving the second portion includes pivoting the second portionabout the pivot joint and rotating the coupling link.
 56. The method ofclaim 50 wherein the first portion includes a hinge support, and whereinthe second portion includes a trailing edge body and a leading edgebody, the leading edge body being connected to the flexible flowsurface, and wherein the airfoil includes a first pivot joint betweenthe trailing edge body and the hinge support, a second pivot jointbetween the trailing edge body and the leading edge body, and a couplinglink pivotably coupled between the hinge support and the leading edgebody, further wherein moving the second portion includes pivoting thetrailing edge body about the first pivot joint, pivoting the leadingedge body about the second pivot joint, and rotating the coupling link.57. The method of claim 50 wherein moving the second portion includesdeflecting the second portion downwardly relative to the first portion.58. The method of claim 50 wherein moving the second portion includesdeflecting the second portion upwardly relative to the first portion.59. The method of claim 50, further comprising moving the second portionback toward the first portion and at least partially sealing the gapbetween the first and second portions.
 60. The method of claim 50,further comprising separating a forward part of the second portion froman aft part of the second portion as the second portion moves from thefirst position to the second position.
 61. A method for varying anairfoil geometry, comprising: moving a movable portion of the airfoilrelative to a wing body of the airfoil from a first position to a secondposition, the movable portion having a trailing edge body pivotablycoupled to the wing body, a leading edge body coupled with a couplinglink to the wing body, and a flexible flow surface coupled between thetrailing edge body and the leading edge body, wherein moving the movableportion includes pivoting the trailing edge body relative to the wingbody; forming an airflow gap by separating at least part of the leadingedge body from the wing body; and changing a shape of the flexible flowsurface from a first shape to a second shape different than the firstshape as the movable portion moves from the first position to the secondposition.
 62. The method of claim 61 wherein moving the movable portionincludes deflecting the movable portion downwardly relative to the wingbody.
 63. The method of claim 61 wherein moving the movable portionincludes deflecting the movable portion upwardly relative to the wingbody.
 64. The method of claim 61, further comprising moving the movableportion back to the first position and at least partially sealing thegap between the wing body and the leading edge body.
 65. The method ofclaim 61, further comprising separating a forward part of the movableportion from an aft part of the movable portion as the movable portionmoves from the first position to the second position.
 66. A method forvarying an airfoil geometry, comprising: moving a movable portion of theairfoil relative to a wing body of the airfoil from a first position toa second position, the movable portion having a trailing edge bodypivotably coupled to the wing body, a leading edge body pivotablycoupled to the trailing edge body, a flexible flow surface coupledbetween the trailing edge body and the leading edge body, and a couplinglink pivotably coupled between the wing body and the leading edge body,wherein moving the movable portion includes pivoting the trailing edgebody relative to the wing body; forming an airflow gap by separating atleast part of the leading edge body from the wing body; and changing ashape of the flexible flow surface from a first shape to a second shapedifferent than the first shape as the movable portion moves from thefirst position to the second position.
 67. The method of claim 66wherein moving the movable portion includes deflecting the movableportion downwardly relative to the wing body.
 68. The method of claim 66wherein moving the movable portion includes deflecting the movableportion downwardly relative to the wing body to the second position, andwherein the method further includes deflecting the movable portionupwardly relative to the wing body to a third position.
 69. The methodof claim 66, further comprising moving the movable portion back to thefirst position and at least partially sealing the gap between themovable portion and the wing body.
 70. The method of claim 66, furthercomprising separating a forward part of the movable portion from an aftpart of the movable portion as the movable portion moves from the firstposition to the second position.